Preheat the oven to 375°F (190°C).
In a large skillet over medium heat, cook the ground beef, diced onion, and minced garlic until the beef is browned and the onion is softened, about 7-8 minutes. Drain excess fat.
Add the thawed mixed vegetables, salt, black pepper, dried thyme, and paprika to the skillet. Stir to combine and cook for 2 more minutes.
In a medium bowl, whisk together the condensed cream of mushroom soup and milk until smooth.
Add the soup mixture to the skillet with the beef and vegetables. Stir well to combine and cook for 2-3 minutes until heated through.
Spread half of the thawed hashbrowns evenly in the bottom of a 9×13 inch casserole dish.
Pour the beef and vegetable mixture over the hashbrowns and spread evenly.
Top the casserole with the remaining hashbrowns, spreading them evenly.
Sprinkle the shredded cheddar cheese evenly over the top layer of hashbrowns.
Cover the casserole dish with aluminum foil and bake for 30 minutes.
Remove the foil and bake for an additional 10-15 minutes, or until the cheese is melted and bubbly and the hashbrowns are golden brown.
Remove from the oven and let the casserole rest for 5 minutes before serving.